Part-supplying tray feeder and method of picking-up parts in the tray

ABSTRACT

In a tray feeder, in which a drawing section draws a palette from a container and supplies the palette to a pick-up point where a pick-up head of a parts-mounting-apparatus picks up parts, the head starts lowering and halts at a stand-by position before the palette held by the drawing section arrives at the pick-up point. When the drawing section arrives at the pick-up point, the head lowers again from the stand-by position. This mechanism reduces a time necessary for picking up a part.

FIELD OF THE INVENTION

[0001] The present invention relates to a tray feeder supplyingelectronic parts packed in a tray to a part-mounting-apparatus and amethod of picking up parts from the tray.

BACKGROUND OF THE INVENTION

[0002] In a part-mounting-apparatus, a method of using tray feeders isknown as one of the methods of supplying electronic parts, e.g.,semiconductor chips. In this tray feeder, a plurality of parts arepacked in a planar condition in these trays, and the trays areaccommodated in a container such as a magazine. Respective trays aresequentially taken out according to the order of parts to be supplied,and the parts are supplied to a pick-up point where a pick-up head ofthe apparatus picks up the parts.

[0003] In one of conventional magazines, trays are accommodated in avertical direction and a tray is drawn horizontally by a drawingsection, and the drawing section is elevated or lowered to a pick-uppoint. When the drawing section have moved and the tray halts at thepick-up point, a pick-up head moves from a stand-by position to pick upa part from the tray. In other words, at every pick-up action, the headlowers from the stand-by position to the pick-up point and picks up thepart by bringing a nozzle of the head in contact with an upper surfaceof the part contained in the tray. As such, a conventional tray feederrequires the head, at every pick-up action, to move from the stand-byposition to the pick-up point. This results in increasing a cycle timeof part-mounting.

[0004] Further, in the conventional tray feeder discussed above, thetray rises to the pick-up point, and subsequently the head startslowering regardless of types of the parts. Thus a time for lowering thehead varies depending on a thickness of a part, i.e., the head mustlowered additionally in the case of a thin part. In this case, it takesa longer time, which increases the cycle time of the part-mounting.

SUMMARY OF THE INVENTION

[0005] The present invention addresses the problem discussed above, andaims to provide a tray feeder, which can improve productivity byshortening a cycle time of part-mounting, and a method of picking upparts using the tray feeder.

[0006] The tray feeder of the present invention supplies parts to apick-up point where a head of a parts-mounting-apparatus picks up thepart, and the tray feeder comprises the following elements:

[0007] (a) a drawing section for drawing a palette—holding a tray inwhich parts are packed—from a container accommodating the palette, andholding the palette;

[0008] (b) a lift for elevating or lowering the drawing section;

[0009] (c) a controller for controlling the head to start loweringbefore the palette drawn reaches a pick-up point;

[0010] Another tray feeder of the present invention comprises thefollowing elements:

[0011] (a) a drawing section for drawing a palette—holding a tray inwhich parts are packed—from a container accommodating the palette, andholding the palette;

[0012] (b) a lift for elevating or lowering the drawing section;

[0013] (c) a timing setter for setting a timing—for a pick-up head tostart lowering from a stand-by position—in relation to a height of thedrawing section and responsive to types of the parts packed in thepalette; and

[0014] (d) a controller for controlling the head to start lowering fromthe stand-by position when the drawing section reaches the height set inrelation to the timing.

[0015] A method of picking up parts from a tray according to the presentinvention comprises the following steps:

[0016] (a) drawing a palette—holding a tray in which parts arepacked—from a container by a drawing section which can be elevated orlowered, and then holding the palette;

[0017] (b) controlling a pick-up head of a parts-mounting-apparatus tostart lowering before the palette drawn by the drawing section reaches apick-up point; and

[0018] (c) picking up a part from the pick-up point by the head afterthe palette reaches the pick-up point.

[0019] Another method of picking up the parts comprises the followingsteps:

[0020] (a) drawing a palette—holding a tray in which parts arepacked—from a container by a drawing section which can be elevated orlowered, and then holding the palette;

[0021] (b) starting to lower the head when the drawing section reachesthe height set in relation to a timing of the head starting to lower andresponsive to types of parts packed in the palette, in a course of thedrawing section, which draws and holds the palette, rising toward apick-up point; and

[0022] (c) picking up a part from the pick-up point by the head afterthe palette reaches the pick-up point.

[0023] According to the present invention, before the palette held bythe drawing section arrives at the pick-up point, the pick-up headstarts lowering from the stand-by position, thereby reducing a time forpicking a part up. Further, before the drawing section arrives at theheight of pick-up point, the head starts lowering from the stand-byposition with a timing set responsive to types of the parts. Thismechanism also reduces a time for picking a part up, and as a result,the total time for part-mounting can be reduced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is a lateral view of a parts-mounting-apparatus to which aparts-supplying tray feeder is linked in accordance with a firstexemplary embodiment of the present invention.

[0025]FIGS. 2A, 2B, 3A and 3B illustrate steps of picking a part up fromthe tray shown in FIG. 1.

[0026]FIGS. 4A, 4B, 5A and 5B illustrate steps of picking a part up inaccordance with a second exemplary embodiment of the present invention.

[0027]FIG. 6 illustrates how a lowering timing of a pick-up head is setin accordance with a pick-up method employed in the second exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0028] Exemplary embodiments of the present invention are demonstratedhereinafter with reference to the accompanying drawings.

[0029] First Exemplary Embodiment

[0030]FIG. 1 is a lateral view of a parts-mounting-apparatus to which aparts-supplying tray-feeder is linked in accordance with the firstexemplary embodiment of the present invention. First, the tray feeder isdescribed with reference to FIG. 1.

[0031] In FIG. 1, tray feeder 1 comprises base member 3 supported bycasters 2, and frames 4, 5 standing on base member 3. Container 10 formagazines is fixed to frame 5. Two magazines 11 are accommodated incontainer 10. Numbers of palettes 15 are stacked in each magazine 11.Door 12 is disposed behind container 10 so that magazine 11 can bemounted or detached therethrough.

[0032] Lift 8 including motor 6 and feed screw 7 is equipped to frame 4.Lift 8 is driven, so that drawing section 9 rises and falls as shownwith arrow marks in FIG. 1. Drawing section 9 draws palette 15 housed inmagazine 11 and holds it on the upper face thereof. Drawing section 9 iselevated, so that palette 15 held by drawing section 9 moves to apick-up point, where a pick-up head of the apparatus comes to pick apart up.

[0033] Discharge section 13 is disposed above magazine 11, and dischargesection 13 accommodates parts not mounted but to be discharged. Supplysection 14 is disposed above discharge section 13, and supply section 14takes out a palette having a vacant tray from which parts have beenpicked up or puts a palette again into line.

[0034] A tray (not shown) is mounted to palette 15 housed in magazine11. In this tray, numbers of parts are packed in matrix. Drawing section9 is equipped with a palette-moving-mechanics (not shown). Thismechanics draws palette 15 from magazine 11 and puts it onto drawingsection 9, or inserts palette 15 again into magazine 11.

[0035] Drawing section 9 rises up to the pick-up point of a part by head21, in other words, the tray mounted to palette 15 drawn from magazine11 is supplied to the pick-up point by elevating drawing section 9. Thenthe part picked up by head 21 is mounted to board 22 positioned at amounting section.

[0036] Motor 6 is equipped with an encoder. The encoder counts therotation of motor 6, thereby detecting a height position of drawingsection 9. The detection result is transferred to controller 24 ofparts-mounting-apparatus 20. Controller 24 controls an operation ofhead-driving-mechanics 23 which drives head 21. Thus, the heightposition of drawing section 9 can be related to a rise/fall timing ofhead 21. In other words, when drawing section 9—in a rising processholding palette 15—arrives at a predetermined height, head 21 can startor stop rising/falling.

[0037] This mechanism discussed above allows controller 24 to startlowering head 21 before palette 15 on drawing section 9 arrives at thepick-up point. The height position of drawing section 9 can be setthrough inputting numerical data into controller 24 by input section 25.Therefore, the head's timing of starting to lower from the stand-byposition can be set in relation to the height position of drawingsection 9. This height position is set responsive to types of partspacked in palette 15, i.e., both of input section 25 and controller 24function as a timing setter.

[0038] The parts-supplying tray-feeder used in the first embodimentproves that when drawing section 9 arrives at the height positiondetermined in relation to the head's timing of starting to lower,controller 24 controls mechanics 23 so that head 21 starts lowering.

[0039] An operation of the tray feeder used in the first embodiment isdemonstrated hereinafter. In FIG. 1, palette 15 containing the parts isaccommodated at a given place in magazine 11. Whenparts-mounting-apparatus 20 starts mounting, drawing section 9 moves toa height of palette 15 containing the parts to be mounted. Then thispalette 15 is drawn onto drawing section 9 and held.

[0040] Parts-supplying process from this point onward is described withreference to FIG. 2A-FIG. 6. FIGS. 2A, 2B, 3A and 3B describe a methodof picking up the parts from the tray shown in FIG. 1.

[0041] First, in FIG. 2A, part 16 is placed in a tray (not shown) onpalette 15 drawn onto drawing section 9 from magazine 11. Part 16 isenlarged in FIG. 2A for easy understanding.

[0042] Next, drawing section 9 is elevated by lift 8 along an arrowmark. At this time, pick-up head 21 of the apparatus halts at a stand-byposition above drawing section 9.

[0043] Then as shown in FIG. 2B, when drawing section 9 arrives at agiven height “Hm”, head 21 starts lowering and halts at stand-byposition “Ps” set above the pick-up point. Drawing section 9, on theother hand, continues rising, and stops rising. As shown in FIG. 3A,when palette 15 arrives at pick-up point “Hp” where the part is to bepicked up. At this moment, head 21 starts lowering from stand-byposition “Ps”, and as shown in FIG. 3B, picks up part 16 from palette15. Then head 21 moves above board 22 to mount part 16 to board 22.

[0044] During this pick-up operation, head 21 starts lowering beforepalette 15 arrives at pick-up point “Hp”, and when palette 15 arrives atpick-up point “Hp”, head 21 has already arrived at stand-by position“Ps” substantially close to pick-up point “Hp”. Therefore, thismechanism allows head 21 to lower to a place only a bit high fromstand-by position “Ps” at the pick-up operation. A time necessary foreach pick-up operation can be thus reduced, and as a result, theproductivity of parts-mounting-apparatus can be improved.

[0045] Second Exemplary Embodiment

[0046]FIGS. 4A, 4B, 5A and 5B illustrate steps of picking a part up inaccordance with the second exemplary embodiment of the presentinvention. In FIG. 4A, part 16 is placed in a tray (not shown) onpalette 15 drawn onto drawing section 9 from magazine 11. Part 16 isenlarged in FIG. 4A for easy understanding.

[0047] Next, drawing section 9 is elevated by lift 8 along an arrowmark. At this time, pick-up head 21 of the apparatus halts at a stand-byposition above drawing section 9.

[0048] Then as shown in FIG. 4B, when drawing section 9 arrives at agiven height “Hm”, head 21 starts lowering. This height “Hm” is used fordetecting a timing and determined responsive to types of parts 16 and inrelation to head's timing of starting to lower.

[0049] The height position for detecting the timing is describedhereinafter. As shown in FIG. 4B, when drawing section 9 arrives atheight “Hm”, head 21 starts lowering. From this moment, drawing section9 continues rising up to pick-up point “Hp” as shown in FIG. 5A. Ittakes time “Td”. On the other hand, when a lower end of a nozzle of head21 arrives at an upper surface of a part on palette 15 at pick-up point“Hp”, it takes time “Tn”. “Td” and “Tn” are set such that both the timesare almost equal to each other. Preferably, both the times are set suchthat drawing section 9 has risen up to point “Hp” slightly before head21 lowers to the given position.

[0050] In other words, this setting is done based on the following twofactors: (1) head's necessary down distance (the distance between thelower end of the nozzle of head 21 at the stand-by position and theupper surface of part 16) and head's lowering speed, (2) drawingsection's necessary up distance (the distance between position “Hm” andpoint “Hp”) and drawing section's rising speed.

[0051] For instance, when part 161 having a rather large thickness ispicked up as shown in FIG. 6, distance “LA” between the upper surface ofpart 161 in palette 15 positioned at pick-up position “Hp” and the lowerend of the nozzle of head 21 is smaller than distance “LB” between thesame points on part 162 having a smaller thickness. Therefore, in thecase of picking up part 161, head 21 may as well starts lowering at adelayed timing comparing to a case of picking up part 162. In otherwords, head 21 may start lowering when drawing section 9 arrives atposition “Hm(A)” higher than position “Hm(B)” assigned to part 162.

[0052] Drawing section 9 continues rising after it arrives at a givenheight “Hm”, shown in FIG. 4B, set responsive to types of parts, andwhen palette 15 arrives at pick-up point “Hp” as shown in FIG. 5,drawing section 9 stops rising.

[0053] During this period, head 21 continues lowering, and completeslowering just after drawing section 9 has stopped rising, and picks uppart 16 on palette 15 at halt, as shown in FIG. 5B. Then head 21 movesabove board 22 to mount part 16 onto board 22.

[0054] In this pick-up operation, head 21 starts lowering from thestand-by position before palette 15 arrives at pick-up point “Hp”. Whenpalette 15 arrives at point “Hp”, head 21 has lowered down to theposition substantially close to pick-up point “Hp”, i.e., the lower endof the nozzle of head 21 stays substantially close to the upper surfaceof part 16 to be picked up.

[0055] Therefore, at a pick-up action, there is little time lag betweenrising action of drawing section 9 and lowering action of head 21, andyet, height position “Hm” for detecting a timing can be set responsiveto types of the parts as mentioned previously. Therefore, when parts ofdifferent thickness are to be picked up, the time lag can be alwaysavoided. Thus a cycle time for each pick-up action responsive to varioustypes of parts can be reduced, and as a result, the productivity of theparts-mounting-apparatus can be improved.

[0056] As discussed above, according to the present invention, thepick-up head starts lowering from the stand-by position before thepalette held by the drawing section arrives at the pick-up point. Thus acycle time for each pick-up action can be shortened, and as a result,the productivity of the parts-mounting-apparatus employing this trayfeeder can be improved.

[0057] Before the drawing section arrives at a height positioncorresponding to the pick-up point of the palette, the pick-up headstarts lowering from the stand-by position at a timing set responsive totypes of the parts. Thus a time to be wasted can be avoided, and anecessary time for the pick-up action can be reduced.

What is claimed is:
 1. A tray feeder for supplying parts to a pick-uppoint where a pick-up head of a parts-mounting apparatus picks up theparts, said tray feeder comprising: a drawing section for drawing apalette, holding a tray which contains the parts, from a container andholding the palette; a lift for elevating and lowering said drawingsection; and a controller for controlling the pick-up head to startlowering before the palette drawn by said drawing section arrives at thepickup point.
 2. The tray feeder as defined in claim 1 furthercomprising: a detector for detecting a height position of said drawingsection.
 3. The tray feeder as defined in claim 2, wherein saidcontroller controls the head to start rising or lowering and stop risingor lowering based on a detection result of the height position of saiddrawing section by said detector.
 4. A tray feeder for supplying partsto a pick-up point where a pick-up head of a parts-mounting apparatuspicks up the parts, said tray feeder comprising: a drawing section fordrawing a palette, holding a tray which contains the parts, from acontainer and holding the palette; a lift for elevating and loweringsaid drawing section; a timing setter for setting a timing for the headto start lowering from a stand-by position responsive to types of theparts contained in the palette and in relation to a height position ofsaid drawing section; and a controller for controlling the head to startlowering when said drawing section arrives at the height position set inrelation to the timing.
 5. A method of picking up parts from aparts-supplying tray, said method comprising the steps of: drawing apalette from a container and holding the palette, which holds a traycontaining the parts, by a drawing section allowed to rise and fall;controlling a pick-up head of a parts-mounting-apparatus to startlowering before the palette drawn by the drawing section arrives at apick-up point; and picking up the parts by the head from the pick-uppoint after the palette arrives at the pick-up point.
 6. The method ofpicking up parts as defined in claim 5, wherein when the drawing sectionarrives at a predetermined height, the head starts lowering and halts ata stand-by position set above the pick-up point.
 7. The method ofpicking up parts as defined in claim 6, wherein the drawing sectioncontinues rising and arrives at the pick-up point while the head haltsat the stand-by position, then the head starts lowering again from thestand-by position.
 8. A method of picking up parts from aparts-supplying tray, said method comprising the steps of: drawing apalette from a container and holding the palette, which holds a traycontaining the parts, by a drawing section allowed to rise and fall;starting to lower a pick-up head of a parts-mounting-apparatus, when thedrawing section—in the course of rising toward the pickup point—whichhas drawn and held the palette, arrives at a predetermined height setresponsive to types of the parts contained in the palette and inrelation to a timing of starting to lower the pick-up head; and pickingup the parts by the head from the pick-up point after the palettearrives at the pick-up point.
 9. The method of picking up parts asdefined in claim 8, wherein the timing of starting to lower the head isset so that a time, necessary for the drawing section to travel from thepredetermined height to the pick-up point, becomes almost equal to atime, necessary for the head to lower down to the pick-up point fromstarting to lower.